1. Field of the Invention
The present invention relates generally to a mobile communication system and method for providing a phone number maintaining service, and in particular, to a mobile communication system and method capable of changing a service provider or a service type while continuously maintaining a phone number previously assigned to a mobile terminal in spite of a change in service provider for the mobile terminal.
2. Description of the Related Art
Generally, in order to receive a mobile communication service provided by a service provider, a user subscribes to a desired mobile communication service provided from the service provider, using his or her mobile terminal. In this case, the service provider stores, in the user's mobile terminal, information necessary for providing the corresponding mobile communication service. Such information is used by the mobile terminal to perform a call service through a service provider network. The “service provider network” refers to a communication network set up by a service provider so that the mobile terminal can perform a mobile communication service.
The information stored in the mobile terminal for a mobile communication service is called NAM (Number Assignment Module) information. The NAM information includes a mobile identification number (MIN) and a service provider identification number (SPID). The mobile identification number is used by a service provider to uniquely identify a mobile terminal, and the service provider identification number indicates a selected service provider.
Conventionally, when a user wishes to change a current service provider, the user must discard a current service provider identification number of the current service provider, and then store a new service provider identification number of a new service provider that provides a new mobile phone service. However, it is troublesome for both the user and the service provider to change the service provider identification number stored in the mobile terminal. In addition, after changing the service provider, the user must inconveniently inform his or her acquaintances of the change in the service provider. Therefore, there have been many demands for a method capable of allowing a user to continuously use the current service provider identification number although the user changes the service provider.
Meanwhile, due to the introduction of free competition into the communication business and removal of barriers between communication companies, phone number resources have a tendency toward opening, centering around advanced countries. Accordingly, a new service provider who wishes to enter the communication business is required to allow the user to continuously use a phone number assigned by the previous service provider. In addition, even the existing service provider proposes a method for allowing the user to continuously use a phone number previously assigned by another service provider regardless of a change in service provider.
Recently, there have been proposed various services provided to allow a user to continuously use a previously assigned phone number in spite of a change in service provider. However, such proposals require interlinking among communication networks and enormous expense for the interlinking, and cause a complexity problem. In addition, as boarders between nations or between service providers in terms of the communication business becomes obscure, the respective nations and service providers have different interests in various parts such as administrative regulation, mediation, service method, opinion decision, etc. Therefore, it is difficult to standardize and realize the proposed inter-service provider phone number maintaining service.